Autonomous lawn mower and a system for navigating thereof

ABSTRACT

A system and method for an autonomous lawn mower comprising a mower body having at least one motor arranged to drive a cutting blade and to propel the mower body on an operating surface via a wheel arrangement, wherein the mower body includes a navigation system arranged to assist a controller to control the operation of the mower body within a predefined operating area.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/312,215 filed Dec. 20, 2018, which is a national stage filing under35 U.S.C. § 371 of International Application No. PCT/CN2017/082005 filedApr. 26, 2017, which claims foreign priority benefits to Hong KongPatent Application No. 16107657.1 filed Jun. 30, 2016, and which theentire contents of all applications are incorporated herein byreference.

TECHNICAL FIELD

The present invention relates to an autonomous lawn mower and a systemfor navigating thereof, and particularly, although not exclusively, toan autonomous lawn mower which uses a navigating system to control thenavigation of the autonomous lawn mower during its operation.

BACKGROUND

The maintenance of lawns requires a significant amount of manual labourincluding constant watering, fertilizing and mowing of the lawn tomaintain a strong grass coverage. Although watering and fertilizing cansometimes be handled with minimal effort by use of a sprinkler orirrigation system, the mowing process is one process that demands asignificant amount of physical effort from gardeners.

Designers and manufacturers of lawn mowers have attempted to manufactureautonomous lawn mowers for some time to replace the traditional pushpull mowers. However, the unpredictability of a landscape together withthe cost of creating an accurate and usable product has meant manyautonomous lawn mowers simply do not perform at an adequate level ofperformance.

This is in part due to the fact that gardens come in many differentvarieties and shapes, with different elevations and profiles. Thus theautonomous mowers have had significant trouble in navigating thesedifferent types of terrain. In turn, many push mowers are stillpreferred by users as their performance and control can still bemanually controlled to overcome problems associated with differentlandscape profiles.

SUMMARY OF THE INVENTION

In accordance with a first aspect of the present invention, there isprovided an autonomous lawn mower comprising: a mower body having atleast one motor arranged to drive a cutting blade and to propel themower body on an operating surface via a wheel arrangement, wherein themower body includes a navigation system arranged to assist a controllerto control the operation of the mower body within a predefined operatingarea.

In an embodiment of the first aspect, the navigation system includes aplurality of navigation modules, each arranged to obtain navigationinformation associated with the navigation of the lawn mower.

In an embodiment of the first aspect, the navigation information isfurther processed by the controller to control the operation of the lawnmower.

In an embodiment of the first aspect, the navigation informationincludes a distance and direction travelled by the wheel arrangement ofthe mower, a surveyed representation of the predefined operating area, alocation of obstacles proximate to the lawn mower, directions andaccelerations of the lawn mower or any combination of one or morethereof.

In one example embodiment, the direction of the mower can be obtained bya magnetometer arranged to provide a bearing of the mower, whilst theorientation of the mower, in 3 axes, may be obtained by a gyroscopearrangement. The gyroscope and magnetometer may be integrallyimplemented within an Inertial measurement unit (IMU) with anaccelerometer or a barometer.

In an embodiment of the first aspect, the navigation system includes anodometry module arranged to track the movement of the mower body on theoperating surface.

In an embodiment of the first aspect, the odometry module is arranged totrack the movement of the mower body on the operating surface bydetermining the rotation distance of at least one wheel of the wheelarrangement.

In an embodiment of the first aspect, the odometry module includes oneor more sensors arranged to detect a rate of rotation of the each of atleast one wheel of the wheel arrangement.

In an embodiment of the first aspect, the rate of rotation of each ofthe wheels is applied to a transmission ratio to determine the rotationdistance of the wheel.

In an embodiment of the first aspect, the rate of rotation of the motoris applied to a transmission ratio determine the rotation distance ofthe wheel.

In an embodiment of the first aspect, the one or more sensors aredisposed onto each driving motor arranged to drive a pair of opposingwheels of the wheel arrangement.

In an embodiment of the first aspect, the odometry module is arranged tocommunicate with the one or more sensors disposed onto each drivingmotor to determine the distance and direction travelled of each of thepair of opposing wheels.

In an embodiment of the first aspect, the odometry module is arranged totransmit the rotation distance and the direction of rotation of each ofthe pair of opposing wheels to the navigation system.

In an embodiment of the first aspect, the navigation system includes anoptical surveying module arranged to scan and survey the proximate areaaround the mower to devise the surveyed representation of the predefinedoperating area.

In an embodiment, the term optical surveying module may include anysurveying modules that are capable of assisting the mower to “see” itssurroundings. In these since, the term “optical” may include surveyingmodules that uses light based technologies, including lasers or cameraswhich object recognition processing. However, it is understood that theoptical surveying module may also assist the mower to “see” itssurroundings by use of non-light based technologies, such as by radiowaves (radar) or sound waves. Thus the term “optical” in this sense mayreference light based technologies or “optical” in the sense that itassists the mower to “see” without necessarily using light basedtechnologies.

In an embodiment of the first aspect, the optical surveying module isfurther arranged to use an optical means to scan and survey theproximate area around the mower.

In an embodiment of the first aspect, the optical surveying module isplaced at an elevated position on the mower body.

In an embodiment of the first aspect, the optical surveying module is aLIDAR unit.

In one embodiment, there may be more than one LIDAR unit.

In an embodiment of the first aspect, the navigation system furtherincludes a sonic or supersonic obstacle detection module arranged to usesound waves to detect any obstacles proximate to the mower.

In one embodiment, there may be a plurality of sonic or supersonicobstacle detection modules.

In an embodiment of the first aspect, the sonic obstacle detectionmodule is a sonar unit.

In an embodiment, the sonic obstacle detection module is a laser sensor.

In an embodiment, the sonic obstacle detection module is an Infrared(IR) unit.

In an embodiment, the sonic obstacle detection module is a radio wave(RADAR) unit.

In an embodiment of the first aspect, the navigation system furtherincludes an inertial measurement unit (IMU) arranged to measure andrecord any physical forces subjected on the lawn mower.

In an embodiment of the first aspect, the inertial measurement unit isremovable from the lawn mower for physical manipulation by the user.

In an embodiment of the first aspect, the navigation system may alsoinclude a satellite navigation system, such as a GPS system arranged toidentify the position of the mower, the direction of travel and theground speed of the mower.

In an embodiment of the first aspect, the navigation system furtherincludes additional sensors arranged to provide navigation information,including GPS coordinates, “cliff” infrared sensors, water/rain sensors,edge sensors, light sensors or any one or more combination thereof.Communication ports such as ports which may be arranged to communicatewith WiFi, Bluetooth, Mobile telephony protocols, radio frequency, DECT,RFID or any other communication protocols may also be used to exchangenavigation information or to assist in the navigation process eitherindividually or in combination with any sensor.

In accordance with a second embodiment of the present invention, thereis provided a system for navigating an autonomous lawn mower comprising:a plurality of navigation modules, each arranged to obtain individualnavigation information associated with the navigation of the autonomousmower; wherein, the plurality of navigation modules operate during aninitialisation mode to generate a virtual representation of an operationarea of the lawn mower; and during an operation of the lawn mower, thevirtual representation of the operation area is processed withnavigation information obtained by the plurality of navigation moduleswhen the lawn mower is operating.

In an embodiment of the second aspect, the virtual representation of theoperation area is compared with navigation information obtained by theplurality of navigation modules when the lawn mower is operating tolocate and navigate the lawn mower during operation.

In an embodiment of the second aspect, the plurality of navigationmodules include an odometry module arranged to track the movement of themower body on the operating surface by determining the rotation distanceof at least one wheel of the wheel arrangement.

In an embodiment of the second aspect, the plurality of navigationmodules include an optical surveying module arranged to scan and surveythe proximate area around the mower to devise the surveyedrepresentation of the predefined operating area.

In an embodiment of the second aspect, the plurality of navigationmodules includes a sonic obstacle detection module arranged to use soundwaves to detect any obstacles proximate to the mower.

In an embodiment of the second aspect, the plurality of navigationmodules includes an inertial measurement unit arranged to measure andrecord any physical forces subjected on the lawn mower.

In an embodiment of the second aspect, the plurality of navigationmodules includes a satellite navigation module arranged to operate witha satellite navigation system to locate the lawn mower and to establisha direction of travel and speed of the lawn mower.

In an embodiment of the second aspect, the plurality of navigationmodules includes an Infrared (IR) module arranged to interact withanother optical or IR system to communicate navigation information withthe mower.

This example embodiment is particularly advantageous where the lawnmower must perform manevours in tight spaces, such as when it isnecessary to manuvour the lawn mower into its docking station, where anIR system implemented on or adjacent to the docketing station and themower can assist in navigating the mower into the docketing station asthe IR can communicate the location of the mower relative to portions ofthe docketing station.

In an embodiment of the second aspect, the initialisation mode isperformed by a user to define one or more operation area of the lawnmower.

In an embodiment of the second aspect, the user defines an operationarea of the lawn mower by controlling the mower around the perimeter ofthe one or more operation area.

In an embodiment, the user may also define an exclusion area of the lawnmower by controlling the mower around the perimeter of one or morenon-operation areas.

In an embodiment, the user may also define a movement area of the lawnmower by controlling the mower within the boundary area between theoperation area and the exclusion area, with the blade mechanismdeactivated.

In accordance with a third embodiment of the present invention, there isprovided an autonomous lawn mower comprising: a mower body having atleast one motor arranged to drive a cutting blade and to propel themower body on an operating surface via a wheel arrangement, wherein themower body includes a navigation system arranged to assist a controllerto control the operation of the mower body within a predefined operatingarea; and a battery module arranged to provide power supply to themotor; wherein the battery module is placed at a lower position withinthe rear mower body.

In an embodiment of the third aspect, the battery module is arranged ata tilted angle with respect to the operating surface to facilitate theaccess to the battery module.

In an embodiment of the third aspect, the mower body is further provideda battery cover arranged to cover the access to the battery module.

In accordance with a fourth embodiment of the present invention, thereis provided an autonomous lawn mower comprising: a mower body having atleast one motor arranged to drive a cutting blade and to propel themower body on an operating surface via a wheel arrangement, wherein themower body includes a navigation system arranged to assist a controllerto control the operation of the mower body within a predefined operatingarea; wherein the mower body further includes a height adjustment systemarranged to assist the controller to control the operation of thecutting blade within a predefined operating height.

In an embodiment of the fourth aspect, the height adjustment systemincludes one or more sensors arranged to determine the height of thecutting blade.

In an embodiment of the fourth aspect, the height adjustment system isarranged to communicate with the one or more sensors to determine thenumber of rotations required by the cutting blade to reach thepredefined operating height.

In accordance with a fifth embodiment of the present invention, there isprovided an autonomous lawn mower comprising: a mower body having atleast one motor arranged to drive a cutting blade and to propel themower body on an operating surface via a wheel arrangement, wherein themower body includes a navigation system arranged to assist a controllerto control the operation of the mower body within a predefined operatingarea; wherein the cutting blade is pivotally connected to and driven bya motor-driven disc.

In an embodiment of the fifth aspect, the cutting blade is arranged toswing in a first direction by the motor-driven disc and swing in asecond direction if the cutting blade contacts any obstacles.

In an embodiment of the fifth aspect, the first direction corresponds tothe rotating direction of the motor and the second direction is oppositeto the first direction.

In accordance with a sixth embodiment of the present invention, there isprovided an autonomous lawn mower comprising: a mower body having atleast one motor arranged to drive a cutting blade and to propel themower body on an operating surface via a wheel arrangement, wherein themower body includes a navigation system arranged to assist a controllerto control the operation of the mower body within a predefined operatingarea; wherein the mower body further includes a cutter module arrangedto trim the edges of the predefined operating area.

In an embodiment of the sixth aspect, the cutter module is placed at aposition underneath the mower body and adjacent to the operatingcircumference of the cutting blade.

In an embodiment of the sixth aspect, the cutter module is removablyengaged with the mower body through a locking mechanism.

In accordance with a seventh embodiment of the present invention, thereis provided an autonomous lawn mower comprising: a mower body having atleast one motor arranged to drive a cutting blade and to propel themower body on an operating surface via a wheel arrangement, wherein themower body includes a navigation system arranged to assist a controllerto control the operation of the mower body within a predefined operatingarea; wherein at least part of the cutting blade is surrounded by ablade guard.

In an embodiment of the seventh aspect, at least a partial edge of theblade guard is further provided a toothed comb.

In an embodiment of the seventh aspect, the partial edge provided withthe toothed comb is substantially perpendicular to the operatingdirection of the lawn mower.

In accordance with a eighth embodiment of the present invention, thereis provided an autonomous lawn mower comprising: a mower body having atleast one motor arranged to drive a cutting blade and to propel themower body on an operating surface via a wheel arrangement, wherein themower body includes a navigation system arranged to assist a controllerto control the operation of the mower body within a predefined operatingarea; a battery module arranged to provide power supply to the motor;and a detachable docking module arranged to provide battery charging tothe battery module.

In an embodiment of the eighth aspect, the navigation system is furtherarranged to locate the mower with reference to the detachable dockingmodule.

In an embodiment of the eighth aspect, the navigation system directs themower towards the detachable docking module.

In an embodiment of the eighth aspect, the navigation system includes animaging module for obtaining the information associated with theposition of the detachable docking module.

In an embodiment of the eighth aspect, the detachable docking module isarranged to provide the imaging module an indication associated with theposition of the detachable docking module.

In an embodiment of the eighth aspect, the indication is represented ina graphical representation.

In an embodiment of the eighth aspect, the navigation system includes anoptical surveying module for obtaining the information associated withthe position of the detachable docking module.

In an embodiment of the eighth aspect, the optical surveying module isarranged to scan and survey the proximate area around the mower todevise the surveyed representation of the predefined operation area,thereby locating the position of the detachable docking module.

In an embodiment of the eighth aspect, the navigation system includes aninduction wire system for obtaining the information associated with theposition of the detachable docking module.

In an embodiment of the eighth aspect, the induction wire systemincludes at least one sensor arranged to communicate with a coil of thedetachable docking module in an electromagnetic communication.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way ofexample, with reference to the accompanying drawings in which:

FIG. 1 is an illustration of an autonomous lawn mower in accordance withone embodiment of the present invention;

FIG. 2 is a block diagram illustrating an example of various controlsystems and modules of the autonomous lawn mower of FIG. 1;

FIG. 3 is a diagram illustrating an example implementation of anodometry module on a pair of opposing wheels of the autonomous lawnmower of FIG. 1;

FIG. 4 is a top view of an operation of an optical surveying module forthe autonomous lawn mower of FIG. 1;

FIG. 5 are illustrations of an example implementation of an opticalsurveying module for the autonomous lawn mower of FIG. 1;

FIG. 6 is a top and front view of an example implementation of a sonicobstacle detection module for the autonomous lawn mower of FIG. 1;

FIG. 7 is a perspective view of an example placement of an inertialmeasurement unit (IMU) module for the autonomous lawn mower of FIG. 1;

FIG. 8 is an example block diagram illustrating an example operation ofan initialisation process for the autonomous lawn mower of FIG. 1;

FIG. 9 is a block diagram illustrated the process flow of theinitialisation process of FIG. 8;

FIG. 10 are illustrations of an example implementation of a batterymodule for the autonomous lawn mower of FIG. 1;

FIG. 11 are illustrations of an example implementation of a heightadjustment system for the autonomous lawn mower of FIG. 1;

FIG. 12 is a diagram illustrating an example implementation of theheight adjustment system of FIG. 12;

FIG. 13 is yet another illustration of an example implementation of theheight adjustment system of FIG. 12;

FIG. 14 are illustrations of an example implementation of cutting bladesarrangement for the autonomous lawn mower of FIG. 1;

FIG. 15 are illustrations of an example implementation of a cuttermodule for the autonomous lawn mower of FIG. 1;

FIG. 16 are illustrations of an example implementation of a blade guardfor the autonomous lawn mower of FIG. 1;

FIG. 17 is a perspective view of an example implementation of a dockingmodule with the autonomous lawn mower of FIG. 1;

FIG. 18 is a front and side view of the docking module and theautonomous lawn depicted in FIG. 17;

FIG. 19 is a perspective view of the docking module depicted in FIG. 17with graphical indication; and

FIG. 20 is a top view of an example implementation of an induction wiresystem of the autonomous lawn mower.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to FIG. 1, there is provided an illustration of anautonomous lawn mower comprising: a mower body having at least one motorarranged to drive a cutting blade and to propel the mower body on anoperating surface via a wheel arrangement, wherein the mower bodyincludes a navigation system arranged to assist a controller to controlthe operation of the mower body within a predefined operating area.

In this example, the autonomous lawn mower 100 is arranged to operate ona lawn or grass grown surface so as to cut the grass. This action iscommonly known as “mow the lawn” and is often undertaken by gardenersand landscape workers to maintain a lawn surface. The term autonomouslawn mower 100 may also include any type of grass cutting device or lawnmower which can operate autonomously, that is, with minimum userintervention. It is expected that user intervention at some point isrequired to set up or initialize the mower or to calibrate the mowerwith specific commands, but once these procedures have been undertaken,the mower 100 is largely adapted to operate on its own until furthercommands are required or if servicing, calibration or error correctionis required. Accordingly, autonomous lawn mowers may also be known asautomatic lawn mowers, self-driven lawn mowers, robotic lawn mowers orthe like.

In this embodiment as shown in FIG. 1, the autonomous lawn mower 100, orreferred to as the lawn mower or mower, includes a frame or housing 102which supports the operating components of the mower 100. Theseoperating components may include, without limitation at least one motor,such as an electric motor, which is arranged to drive the blades of themower so as to cut the grass of a lawn to which the mower is mowing. Theat least one motor may also be used to drive the mower itself via themeans of transmission systems, such as gearing mechanisms or gearboxeswhich transmit a driving force to its wheel arrangements 104, althoughpreferably, as is the case of this embodiment, separate motors are usedto drive the mower along its operating surface with each rear wheel 104Rhaving its own individual motor and gearbox. This is advantageous inthat manoeuvring the mower may be implemented by simple control of eachof these motors. It is important to note that the term wheelarrangements may also include driving arrangements that are formed fromvarious different types and combination of wheels, including tracks(such as in tank tracks), chains, belts (such as in snow belts) or otherforms of driving arrangements.

Preferably, as shown in the embodiment of FIG. 1, the mower 100 includesa navigation system which operates to locate and navigate the moweraround a working area so that the mower can cut the grass of a workingarea. The navigation system may include a number of specific navigationmodules each arranged to provide individual navigation informationobtained for the mower 100. In turn, the navigation information obtainedor determined by each of these navigation modules are then returned tothe navigation system for transmission to a controller. Upon processingof the navigation information by the controller, the controller may thengenerate commands which are used to control the movement and operationof the mower within a work or operation area.

These navigation modules may include at least the follow:

-   -   An odometry module 106 arranged to determine the distance        travelled by the wheels 104 so as to assist in the determination        of the location of the mower 100 from a starting point;    -   An inertial measurement unit (IMU) module 108 arranged to        measure the force of movement of the mower by detecting and        recording various forces which are subjected on the mower 100,        including the direction of movement, force of movement, magnetic        bearing of movement, acceleration and gyroscopic movements. In        some example implementations, more than one IMUs may be used to        improve accuracy, since additional IMUs will assist in        eliminating errors over time    -   An optical surveying module 110 arranged to use an optical means        to scan and survey the immediate area around the mower 100. An        example implementation of this optical surveying module 110 may        be the placement of a LIDAR unit on the mower body 102 so as to        scan a surrounding area of the mower 100 to produce a dynamic        map of the immediate spatial environment proximate to the mower        100;    -   A barometric sensor arranged to measure the air pressure        surrounding the mower. Such an arrangement may be advantageous        in that the altitude of the mower can be measured based on the        air pressure changes it experiences as the mower moves along its        operation areas or relative to its docking station and thus        assist in its localization and navigation.

Preferably, the barometric sensor can also be calibrated, eitherautomatically or manually by the use of weather information that istransmitted to the mower via its communication modules;

-   -   A sonic or ultrasonic obstacle detection module 112 arranged to        use sound waves to detect if there are any obstacles proximate        to the mower so as to assist the mower with avoiding these        obstacles, or in some examples, to approach one or more objects,        whilst avoiding direct contact or collision with the object so        as to enhance the operation of the mower by navigating the mower        to be proximal to certain objects for operation, whilst avoiding        a collision with the objects. Example implementations of the        sonic obstacle detection module may be by the use of SONAR        sensors or ultrasonic sensors which can detect obstacles; and,    -   Other additional navigation modules (not shown) may also be        implemented to communicate with the navigation system so as to        provide further input to the navigation system to adjust and        control the mower, including:        -   GPS sensors which can be used to obtain a GPS coordinate of            the mower 100. In some examples, the mower may be            implemented to use “RTK GPS” or Real Time Kinematic GPS            which includes two GPS modules, one fixed and one in the            mower in addition to advanced GPS information to determine            the precise position of the mower within the mowing area and            world;        -   Compass sensors to obtain a compass bearing of the mower            100;        -   Rain sensors or water sensors to detect if the immediate            environment is subject to rain, high levels of moisture or            entry of the mower into a puddle of water and if so, adjust            or terminate operation of the mower 100;        -   Edge sensors or cliff sensors to detect if the mower 100 has            reached an edge or a cliff whereby any further movement may            cause the mower 100 to experience a fall;        -   Light sensors to detect light or time of day and adjust            operation accordingly, including the switching on of warning            lights; and,        -   Other additional sensors and function modules, such as            clock, WiFi, Bluetooth, GSM, RF, DECT, or any other            communication protocol modules arranged to receive            COMMUNICATION PROTOCOLS external information received via            communications connections such as weather reports or remote            commands to enhance and control the operation of the mower            100.

These navigation modules are each arranged to obtain, detect anddetermine a set of navigation related information, which are in turnarranged to be processed by a processor on the controller to devisesuitable commands to operate the mower 100. As it will be explainedbelow with reference to FIGS. 8 and 9, in one example, the autonomouslawn mower will operate by moving away from a docking station (notshown) which will form a start and return point for the mower. The mower100, when departing the docking station may then use the navigationsystem to assist with navigating the mower 100 around a work oroperation area by cutting the lawn in the operating area, and thenproceeding to navigate its way back to the docking station.

With reference to FIG. 2, there is provided a block diagram of theautonomous lawn mower 100 which illustrates the components of theautonomous lawn mower 100. In this embodiment, the mower 100 includes acontroller/processor 202 which may be implemented as a computing device,or as one or more control boards, with each having one or moreprocessors arranged to receive and analyse the information received andto provide instructions to the mower in order to operate the mower.Preferably, the controller/processor 202 is implemented with a mainprinted circuit board assembly (PCBA) arranged to have two processors onthe PCBA and to operate together with an additional computing module.Several of the sensor PCBAs may also have their own individualMicrocontroller units (MCUs).

The controller/processors 202 is arranged to receive navigationinformation from the navigation system 204 of the mower 100 and in turn,upon the receipt of this navigation information, will process thenavigation information with existing information already accessible bythe controller 202 such as the control algorithm 206 or predefined mapof the operating area 208 to generate various commands to each of themower operating components, including the drive motors arranged to drivethe mower 210 and/or the blade motors which operates the blades 212.

As shown in FIG. 2, the navigation system 204 includes the odometrymodule 220, which includes wheel sensors 232 to detect the rotationaldisplacement of the wheels of the mower 100, the optical surveyingmodule 222 (such as an LIDAR unit 222L), the IMU unit 226, the sonicobstacle detection module 224, which may include Sonar sensors 230although other sound wave based obstacle detections methods arepossible. Each of these modules are arranged to provide a specificfunction which are described below with reference to FIGS. 3 to 7 andreturn individual navigation information either detected, calculated,gathered or surveyed, as in the case of the LIDAR unit 222L which isarranged to generate a virtual map 208 representative of the obstaclesor placement of specific objections proximate to the mower 100.

As illustrated in this embodiment, the controller 202 is also arrangedto control the mower drive motors 210 to drive the mower 100 along awork surface within a work area. Preferably, as is the case in thisembodiment, the mower is driven by having a motor placed adjacent toeach of the rear wheels with each motor being arranged to drive eachrear wheel.

In turn, the controller 202 can direct electric current from a powersource, such as a battery 214, to the motors 210 so as to perform acontrolled operation of one or both motors 210. This can allow forforward, reverse and turning actions of the mower 100 by turning one ormore wheels at different speeds or directions.

The controller 202 can also command the blade motor 212 to operate so asto operate the blades to cut the grass of a work surface. To performthese functions, the controller 202 will execute a control routine orprocess 206 which determines the conditions for and when the mower is tobe operated. These commands at least include instructions to command thedirection of travel of the mower 100 and the operation of the blades.Other commands are also possible, including the command of the mower 100to travel to a particular location within a work area, or to return to aspecific location, such as a docking station as well as specificcommands such as the operating speed of the blade motor 212 or theheight of the blade so as to determine the level of grass that is cut.

As it will be explained below with reference to FIG. 8, the controller202 may also be pre-programmed with an initialization routine 228wherein the mower's working area and work surfaces are initiallyidentified. These process may assist in identify the boundaries of aworking area and the categorization that certain surfaces within theboundaries should be avoided (no travel zones) or should not have theblade motor activated 212. Once these working areas are identified, themower 100 can then be controlled by the controller 202 to navigate to astarting point from the docking station, wherein the mower can proceedto cut the grass from the starting point as stipulated by the controlalgorithm 206. The control algorithm 206 may include a specific cuttingprogram, which mows the lawn along a longitudinal axis and then workeach longitudinal axis in a latitudinal form within the working areadefined so as to cut the grass in the working area. Other cuttingprograms are also possible and can be chosen base on the shape andprofile of the working area of the desired operation of a user.

Preferably, as the controller 202 will communicate with each of thenavigation modules of the navigation system 204, the controller 202 may,during initialisation and general operation, receive a large amount ofdifferent navigation information from each of these navigation modules202. In order to process this navigation information so as to determineoperation commands for the mower 100, the controller 202 may first applya filter or an averaging function to all of navigation informationreceived from the navigation system. Such a filtering function may allowthe controller 202 to ignore or minimize any weighting placed onnavigation information obtained from a first navigation module thatappears to be incorrect when compared with navigation informationobtained from other navigation modules. Example filters which can beused includes the Kalman Filter which can be applied to assist withidentifying a “best fit” trend for all navigation information receivedby the controller and in turn, allowing anomalies, deviations orinconsistencies, which may be far away from the average or best fittrend, to be ignored or further investigated.

As an example, the controller 202 may receive navigation informationfrom the, odometry module 220, the sonic obstacle detection module 224and the optical surveying module 222. During processing, the odometrymodule 220 may have tracked that the mower 100 has travelled to aparticular co-ordinate on a virtual map obtained during theinitialization of the mower 100. However, according to the navigationinformation obtained by the IMU and the optical surveying module 222,the location of the mower 100 may be at a distance substantially faraway from the co-ordinates obtained from the odometry module 220. Inthese instances, when the filtering function is applied to allnavigation information of the sonic obstacle detection module 224, theoptical surveying module 222 and the odometry module 220, the “best fit”or “average” may in turn indicate that the co-ordinates of the odometrymodule 220 is an anomaly, as it is completely inconsistent with theother navigation modules. Accordingly, the controller 202 may thenproceed to ignore this anomaly in generating commands to the mower. Itis also expected that the controller 202 may also apply a similarfiltering function to all data obtained from the navigation system andother sensors such as GPS sensors, compass, cliff sensors, water sensorsetc. The Extended Kalman Filter, for example, may be advantageous inthey are able to reduce/eliminate bad data points from each source andto assist in determining which sources of navigation/localization dataare most reliable and use select these sources instead.

In some example embodiments, the filtering function or averagingfunction such as the Kalman Filter can also be applied by eachnavigation module to any navigation information obtained before thenavigation information is communicated to the controller 202. In theseexamples, as sensors and other electronic navigation modules arearranged to obtain data from environmental readings, it is possible thatdue to uncontrolled incidents or other environmental factors may causecertain readings to be incorrect within a short timeframe. Examples ofthese may include the mower experiencing wheel spin, and thus causingerroneous readings by the odometry module 220, or a random or accidentalcollision with an object, such as a football, in which case thenavigation information obtained from the IMU module 226 may also beerroneous.

In these instances, by including a filtering function with eachnavigation module, such anomalies in the data collected by eachnavigation module may be filtered or “cleaned up” before it is sent tothe controller 202. Thus this this would advantageous in that thenavigation information sent to the controller 202 is likely to be moreaccurate, resulting in improved performance and less processing by thecontroller 202.

With reference to FIG. 3, there is illustrated an example of an odometrymodule 220 arranged to be implemented with an autonomous mower 100. Inthis example embodiment, the odometry module 220 is arranged to beimplemented into each of two motors arranged to drive the rear wheels104R of the mower 100, although as a person skilled in the art wouldappreciate, if additional motors are used to drive other wheels of themower 100, than this odometry module 220 can also be implemented intoeach of the motor windings 302.

In this example, the odometry module 202 is arranged to measure thenumber of rotations of the wheels 104R to which the odometry module 202is implemented to operate with. In turn, the number of rotations, whencoupled with the circumference of the wheel 104R will provide anestimation as to the distance travelled by the mower 100 on a worksurface (taking into account any gear ratios, if applicable). As themower 100 may also turn along its work surface by allowing its opposingwheels to spin in opposite directions, such movements and rotation canalso be detected and measured so as to determine the direction and rateof turn of the mower 100 along a work surface.

As illustrated in FIG. 3, the odometry module 202 is implemented onto amotor 302 and gearbox arrangement 304 which drives one of the rearwheels 104R, with each rear wheel 104R having its own motor 302 andgearbox 304. When the motor 302 is energised by its power source, inmost instances by command of the controller 202, the motor will rotate302 and thus also driving a gearbox 304 which is rotatably attached tothe motor 302.

The gearbox 304 will then also transmit this rotational force to thewheels 104R and thus turning the wheels 104R in a desired direction. Asthe gearbox ratio is known, either by presetting at the factory, or useradjustment, the odometry module 202 can thus operate by detecting thenumber of rotation of the motor 302 which can in turn be used tocalculate the number of rotations of the wheel 104R.

In this implementation, the motor has a Print Circuit Board (PCB) 306connected to the motor windings 302 and rotor which is implemented witha number of hall sensors 308. These hall sensors 308 allow a magneticsignal to be detected upon each sensor 308 being rotated passed a magnet(or have a magnet rotated pass the sensor 308) and thus when the motoris rotated, the PCB 306, which is static, will detect the magnets heldin the rotor of the motor 302. The hall sensors 308 located on the PCB306 can thus detect a magnet as it is passed during the rotation of themotor windings 302. In turn, this data from the hall sensors 308 canthen be used to calculate the number of or portions of rotations of themotor 302, which can then be used to calculate the number of rotationsof the wheel 104R via the gearbox 304.

Once the number of rotations is determined, the number of rotations ofeach wheel 104R, including its direction and whether the wheels 10R areundergoing a turning direction, will then be transmitted to thecontroller 202 for processing. In turn, the controller 202 can thenprocess this result with other information from the navigation system204 to ascertain the location of the mower 100.

It is expected that the wheels of the mower 100 may undergo some wheelspin when the mower 100 is in operation, as the surface type may causethe wheels 104R to spin without moving the mower 100. Such wheel spinswill result in error when determining the position of the mower 100.However, such errors are factored into the calculation by the controller202 as other navigation information obtained by other modules of thenavigation system 204 will be used to compensate for any errors of oneindividual navigation module.

In another example implementation, the amount of electric current drawnby the motor 302 may also be measured and compared against the rotationrate detected by the odometry module 202. In such examples, if thecurrent drawn by the motor 302 is very low relative to the number ofrotations detected of the wheel 104R, then the wheels 104R of the mower100 may indeed be spinning along its working surface. Accordingly, suchinformation may also be considered by the controller 202 in determiningthe distance of the mower 100 based on its odometry measurement.

With reference to FIGS. 4 and 5, there is illustrated an example of anoptical surveying module 222 arranged to be implemented with anautonomous mower 100. In this example embodiment, the optical surveyingmodule 222 is implemented by the placement of a Light Detection andRanging (LIDAR) unit 222L on the mower body 102 so as to scan and surveya surrounding area 402 to produce a dynamic map of the immediate spatialenvironment proximate to the mower 100.

In this example, the optical surveying module 222 is a LIDAR unit 222Lon the mower body 102. The LIDAR unit 222L may be implemented to firerapid pulses of laser light which come into contact with objects (suchas the tree 404, chair 406 or LIDAR stakes 408) in the surroundingspatial environment circumferential to the mower 100.

Instrumentation that is part the LIDAR unit 222L receives the reflectedlaser light from these objects and measures the amount of time taken foreach pulse to be reflected back to the LIDAR unit 222L. As the speed oflight is known, the distance between the objects and the LIDAR unit 222Lcan be calculated. A dynamic map of the spatial environment proximate tothe mower is built as a result of rapid successive measurements ofreflected laser light.

With reference to FIG. 4, there is illustrated an example of the opticalsurveying module 222 scanning and surveying the surrounding environmentproximate to a mower 100. The optical surveying module 222, exemplifiedby a LIDAR unit 222L as mentioned previously, is represented by thecircle located at the centre of the square, which represents the mower100. The arrows emanating from the circle represent the laser light 405fired by the LIDAR unit 222L and indicate their direction ofpropagation. The LIDAR unit 222L surveys the spatial environment aroundthe mower 100 by firing rapid pulses of laser light 405 that areincident on objects within the surveyed environment. In this example,such objects are a tree 404 and a chair 406. The laser light 405 isreflected from the objects and detected by the LIDAR unit 222L, and theLIDAR unit 222L may then calculate the distance between the mower 100and the object. The map produced is dynamic because the position of themower 100 relative to any object constantly changes since the mower 100may move during its operation.

Also illustrated in FIG. 4 are LIDAR Stakes 408 represented byrectangles. In one example, a LIDAR Stake 408 may be composed of aplastic stake top and a stake cover. In one alternative example, a LIDARstake 408 may be a LIDAR object or a plurality of grouped LIDAR stakes408. Each LIDAR stake 408 may pertain to fix the LIDAR object to thelawn, and meanwhile provide a visible portion for the LIDAR system to“see” the yard. Optionally, the fixation and the visible portion may beformed integrally. The LIDAR Stake 408 is inserted vertically into theground so that the plastic stake top remains above the surface of theground. Laser light 405L fired from a LIDAR unit that is incident on aLIDAR Stake will be reflected back to the LIDAR unit 222L. A number ofLIDAR Stakes, each suggests an image of a narrow object, may be plantedin series to denote a boundary, several objects grouped closelytogether, or alternatively a single large object, e.g. fake, plasticrocks having a size of approximately 30 cm (L)×50 cm (W)×50 cm (H). TheLIDAR unit on a mower will detect a boundary formed by a series of LIDARStakes and the mower will be prevented from crossing the boundary. Insome advance embodiments, each of the LIDAR Stakes 408 may have a uniquesignature so that the LIDAR unit 222L may differentiate one LIDAR Stake408 from another, in turn allowing the controller 202 to triggerspecific operation commands, such as “no go zones” or “dedicated zones”.

For example, a work surface over which a mower 100 will operate maycontain a swimming pool. It is undesirable for a mower 100 to come intocontact with the water in a swimming pool because this may damage theelectronics within the mower 100. A series of LIDAR Stakes 408 may beinserted periodically around the perimeter of the swimming pool to forma boundary. The LIDAR unit 222L on a mower will detect this boundary andthe mower will not come into contact with the pool enclosed within theboundary.

As illustrated in FIG. 5, the optical surveying module 222 may be asingle LIDAR unit 222L on the mower body 102. Preferably, the LIDAR unit222L is located centrally on the upwards-facing surface of the mowerbody 102 as this allow the LIDAR unit 222L to be positioned so that noother part of the mower body 102 can obstructs any laser light emanatingfrom the LIDAR unit 222L. The LIDAR unit 222L is implemented to bedriven by a motor via a gearing mechanism or belt.

In turn, this embodiment of autonomous lawn mower 100 includes acontroller 202 which may be implemented as a computing device. Thecontroller can direct electric current from a power source to the LIDARunit's motor. When the motor is energized by its power source, in mostinstances by command of the controller, the motor will rotate and thusalso rotating the LIDAR unit 222L. This enables circumferential coverageof the laser pulses fired from the LIDAR unit 222L.

The aforementioned controller 202 may also be pre-programmed with aninitialization routine 228 which serves to initially define the mower'swork area and work surfaces. During this initialization process, theLIDAR unit 222L as implemented on the mower body 102 in this exampleembodiment may then proceed to survey the surrounding environment and inturn identifies the boundaries of a working area during aninitialization process. Certain surfaces within the boundaries may alsobe categorized as areas to be avoided or surfaces where the blade motorshould not be activated. The data gathered by the LIDAR unit 222L duringthis initialization routine may then be used to build a map that can bereferred to as the virtual survey map 208 that can be used when themower 100 operates autonomously.

An exemplification of an initialization routine 228 is further describedbelow with reference to FIG. 8. As shown in FIG. 8, a house may have afront lawn and a back lawn connected by a concrete path. A LIDAR unit222L on a mower 100 may then proceed to survey the surroundingenvironment and identify the cutting perimeters enclosing the front lawnand the back lawn. The controller can activate the blade motor onsurfaces within this perimeter. The user may not desire the blade motorto operate along the concrete path that joins the front lawn and backlawn; hence the path taken by the mower across the concrete path isidentified as a non-cutting path.

Following the execution of the initialization routine 228, the LIDARunit 222L builds a dynamic map in real-time which can then be used to becompared with the stored survey map 208 for the purpose of identifyingthe mower's location on the survey map 208 and in turn, operating themower as needed based on the location.

The utility of this process can be demonstrated through exemplification.The controller 202 may have a command to increase the height of theblade over a particular area of the mower's working area so that thegrass over such area is cut longer than the grass over the rest of theworking area. As the mower traverses its working area, the dynamic mapproduced by the LIDAR unit 222L is compared to the previously generatedsurvey map 208, so that location of the mower is known and hence thecommand can be executed by the controller over the correct area of theworking area.

In one example embodiment, the use of LIDAR may be a primary sensor forthe navigation and localization of the autonomous mower 100. The LIDAR,or also known as the LIDAR Unit or LIDAR module, may include a lasermodule mounted to a rotatable base. The laser module includes a laser orLED sender which sends out a light pulse or signal and a receiver thatreceives the rebounded pulse or signal along with other electronics forcontrol and filtering.

In turn, these pulses or signals captured by the receiver may then becompared to the signal sent by the laser/LED and processed to determinehow far away the object that rebounded is from the system. Preferably,the rotation of the laser module is controlled and synchronized with theaction of the laser module so that a 2-dimensional map of the areasurrounding the LIDAR can be obtained.

In one example, the frequency of the laser module and rotating unitdetermines the measurement sensitivity of the LIDAR unit. In one exampleembodiment of the mower 100, it is preferred that the LIDAR unit will beused preliminarily in order to create a virtual map of the lawnenvironment as the mower is electronically walked around the lawnboundary and any fixed obstacles within said boundary during theinitialization process. This virtual map may then be saved in themower's memory or storage.

When the mower 100 is operated to perform autonomous cutting or at anytime when the mower 100 is operating away from its docking station, theLIDAR system may be arranged to scan and compare what it is currentlydetecting against the stored virtual map in order to determine themower's position within the known garden. The LIDAR could also be usedfor obstacle avoidance by in some examples where the mower wasprogrammed to avoid detected obstacles that are not part of the mappedlawn.

Alternatively, the navigation and localization of the autonomous mower100 may be achieved by camera/visual sensor based navigation methodssuch as visual Simultaneous Localization and Mapping (vSLAM).

With reference to FIG. 6, there is illustrated an example of sonicobstacle detection module 224 arranged to be implemented with anautonomous mower 100. In this example embodiment, the sonic obstacledetection module 224 is implemented by the placement of Sound Navigationand Ranging (SONAR) sensors 602 on the mower 100 to use sound waves todetect if there are any obstacles proximate to the mower 100 so as toassist the mower with avoiding these obstacles.

In this example, the sonic obstacle detection module 224 is implementedwith a plurality of SONAR sensors 602 on the mower body 102. The SONARsensors 602 fire pulses of sound waves which come into contact withobjects in the surrounding spatial environment in front of the mower100.

Instrumentation that is part a SONAR sensor 602 receives the reflectedpulse (echo) and measures the amount of time taken for each pulse to bereflected back to the SONAR sensor 602. As the speed of sound is known,the distance between the objects and the SONAR sensors can becalculated.

As illustrated in FIG. 6, the sonic obstacle detection module 202 mayinclude four SONAR sensors 602 on the mower body 102. Preferably, thefour SONAR sensors 602 may be located on the front-facing surface of themower body as this allows the sensors 602 to detect obstacles in thepath of forward travel. The four SONAR sensors 602 are positioned suchthat no part of the mower body 102 obstructs any pulses of soundemanating from the SONAR sensors 602.

As shown in FIG. 6, the SONAR sensors may be located on the front-facingsurface of the mower body 102 in order to detect object(s) positioned infront of the mower 100 in the direction of the mower's motion, althoughit is possible to also have sonar sensors 602 implemented on the sideand rear of the mower body 102. Detecting object(s) that may obstructthe motion of the mower 100 would enable the controller to executeappropriate commands to avoid colliding with said object(s).

For example, a work surface over which a mower 100 will operate maycontain an object, such as a chair at some distance away from the mower100 which the SONAR sensors 602 detect. The controller 202 may in turnbe arranged to receive this navigation information and, after processingthis navigation information, will generate an appropriate commandnecessary to avoiding this obstacle. Such commands may include a changeof the direction of motion of the mower, stopping the motion of themower, or shutting off the cutting mechanism of the mower depending onthe information received from the sensors.

The navigation information of the sonar sensors 602 is particularlyuseful as obstacles may be placed in front of the mower 100 during itsoperation or may otherwise not be detected during the initialisationprocedures. This is because an operation area of the mower 100, such asa yard, may have traffic from humans, animals or other objects whichchanges the number of obstacles in a work environment. The sonar sensors602 are thus able to detect these obstacles and in turn allow thecontroller 202 to adjust the operation of the mower 100 to accommodatefor these obstacles. The sonar sensors 602 may also be helpful as it maybe implemented to have a short scope of vision and thus the sensors 602may be mounted lower on the mower to see objects that are not tallenough to be seen by the LIDAR units. Furthermore, whilst a LIDAR unitmay in theory replace the sonar sensors 602, sonar sensors 602 may becheaper to implement, particularly for lower portions of the mower whereobstacle avoidance is advantageous.

In one example embodiment, the mower 100 may use a plurality of SONARmodules (SONAR) about the edges of the unit to prevent bumping and/orscraping side obtrusions. For instance, a SONAR located and facingoutwards from the front of the unit is used for obstacle avoidance. ThisSONAR may be arranged to be capable of identifying obstacles in front ofthe unit and notifies the mower. The mower may then check the locationof the obstruction against the known lawn map (or virtual map) createdand saved from the mower's LIDAR system and uses the information of theobstacle in front of it in conjunction with the information of the knownlawn map to navigate around/away from the object.

This example is advantageous in that such an arrangement as described isnot standard for many existing autonomous mowers as most current mowersuse the bumping sensors to detect objects and change direction.

Preferably, in another example, the mower 100 may also have anadditional set of SONAR on the right side of the unit which is the sameside as the perimeter cutter. As some example mowers 100 may have anedge mowing function in which the mower traces around the edge of themapped boundary and uses a secondary cutting mechanism to trim the grasscloser to the edge than the primary cutting means is able. The sideSONAR may in turn be used to measure the distance from the edge of themower to objects, such as fences, along the boundary in order to allowthe mower to navigate close to the object, but avoid bumping and thusscratching the mower's top cover to keep a nicer appearance.

With reference to FIG. 7, there is illustrated an example of an inertialmeasurement unit (IMU) module 226 arranged to be implemented with anautonomous mower 100. In this example embodiment, the IMU module 226 isimplemented by the placement of a removable IMU unit within the body ofthe mower 100 which is arranged to measure the force of movement of themower by detecting and recording various forces which are subjected tothe mower 100.

In this example, the IMU module 226 is a removable IMU unit within thebody 102 of the mower 100. The IMU 226 detects and records variousforces which are subjected on the mower 100, including the direction ofmovement, force of movement, magnetic bearing of movement, accelerationand gyroscopic movements. Preferably, the IMU 226 functions by using atleast one accelerometer to detect the rate of acceleration ordeceleration of the mower, at least one gyroscope to detect thegyroscopic movements of the mower and a magnetometer to detect themagnetic bearing of movement of the mower. The IMU may also furthercomprise an IMU chip and power supply, such as a battery such that itcan continue to be energized when it is removed from the mower 100.

As shown in FIG. 2, the IMU module 226 is connected to the controller202. The controller 202 may be implemented as a computing device whichis arranged to receive the navigation information detected by the IMUmodule 226. Following processing by a processor, suitable commands tooperate the mower 10 can be developed based on the navigationinformation supplied by the IMU module 226.

As illustrated in FIG. 7, the IMU module 226 is implemented within thebody of the mower 100 as an electronic component. The IMU module 226 isrepresented by a rectangle and a possible position of the IMU isindicated by an arrow, being placed below a removable or latched on logoplate which acts as a door to access the IMU 226. Preferably, the IMU226 is placed below an openable cover 702 marked by the mower'smanufacturer's logo on the upward-facing surface of the mower. Theopenable cover would allow access to the IMU 226, whilst protecting theIMU 226 from debris and moisture. Once the cover is opened, a user canthen remove the IMU 226 by lifting it out.

The advantage of a mower 100 in having a removable IMU 226 is that thecalibration of the IMU 226 would be much simpler. As the IMU 226 maydetect at least the acceleration and gyroscopic movements of a unit, itmay be required to undergo calibration after shipping such that it canbe calibrated for its full range of movement. In this sense, by allowingthe IMU 226 to be removable, the user can calibrate the IMU 226 for themower by moving it in all three dimensions, such as by shaking or movingthe IMU in their hand without having to shake or move the entireautonomous mower 100. To achieve this, the IMU may only be connected tothe mower via a cable, and thus allowing a user to shake or move theIMU, although in some examples, where the IMU is entirely removable fromthe mower, the IMU may have its own power supply to remain functionalwhen it is removed entirely from the mower body and thus it may have itsown battery or capacitor to store sufficient power for the calibrationprocess.

As an example, as part of an initialization process a user may berequired to calibrate the IMU 226. A user would remove the IMU 226 fromthe mower body 102 and move the IMU 226 in a “figure of 8” pattern inorder to give the accelerometer and gyroscope components of the IMU avaried range of accelerations and gyroscopic motions to detect andrecord. Being able to remove the IMU for this purpose is advantageous asthe IMU 226 is easier to handle and manipulate when compared with havingto perform the same actions with an entire mower 100, which would bemore heavy, cumbersome and potentially dangerous.

With reference to FIG. 8, there is illustrated an example of aninitialisation process for the autonomous mower 100. In this example,the initialisation process or routine 228, is a set of procedures whichmay be performed by a user so as to initialise the mower 100 forself-operation in a work area.

To initialise the mower 100 for operation, the user may proceed to teachthe mower 100 the boundaries for operation. In so doing, the mower 100can then be taught by the user as to the location and definition of theworking area as well as any travel paths which are required to get tothe different portions of the working area.

As shown in this example, the user can firstly manual operate the mower100 along the perimeters of one or more operation areas so as to teachthe mower the operation areas which are needed to be mowed by the mower.The mower can be operated in this mode by having a handheld controller804 to be operated by a user 802. In this embodiment, the handheldcontroller 804 may include a number of switches and a joystick similarto that of a gaming controller which allows a user 802 to drive themower 100 along the perimeters of the operating surface. This maysometimes be referred to as the “dog walking mode” 800, representativeof a user in “walking” the mower along a path.

When the user 802 drives the mower 100 along these perimeters, the mower100, which would be in an initialization mode (or called the dog walkingmode), may then operate its navigation system so as to continuouslycreate navigation information associated with its proximate environment.This may include, for example:

-   -   the odometry module 220 in recording the distance of travel as        well as the direction of travel;    -   the IMU 226 in measuring the direction of travel;    -   the sonic obstacle detection module 224 in detecting obstacles,        recording the location of these obstacles;    -   the optical surveying module 222 in surveying the proximate area        around the mower and recording the location of obstacles, LIDAR        stakes etc to create a virtual map of the areas around the        mower; and,    -   Any other navigation modules or sensors (e.g. GPS etc) which may        contribute towards refining the navigation information.

Once this navigation information is created, the mower 100 may thenstore this navigation information for use in autonomous operation. Thisstored navigation information, which may be in the form of a virtualmap, may then be processed by the mower 100 with new navigationinformation that is obtained in real time by the navigation systemduring mower operation to devise the location of the mower 100 when inoperation.

In one example, as shown in FIG. 8, the user may start theinitialization process by firstly “dog walking” 800 the mower 100 aroundits operating areas so as to define the operating areas in which themower 100 will operate. As it can be seen, a user's home may include afront lawn 810 and a back lawn 812 with a concrete path 814 in betweenthe front lawn and back lawn. In this case, the user may start the dogwalking process 800 by firstly controlling the mower 100 from the mowerdocking station 816, which is the base for which the mower 100 mayoperate from. This docking station 816 may provide a base for the mowerand can provide several functions, including diagnostic, connectivity toexternal devices and recharging capabilities.

Once the user starts the dog walking process 800, the user can drive themower 100 from the docking station 816 to a perimeter 818 of the workarea and select on the handheld controller 804 to start recording theperimeter 818. The user can then drive the mower around the perimeter818 of their back lawn 812, as an example and in turn, allow the backlawn 812 to be marked by the mower 100 as a first work area. During thistime, the mower 100 is continuously operating its navigation system soas to survey the first work area, including the distance of travel ofthe perimeter 818, the direction of travel and any obstacles which canbe used as a reference to assist with its navigation such as the dockingstation 816, garage 820 and house 822.

The user may then drive the mower onto the concrete path 814 so as tomove the mower 100 towards the front lawn 810 to set a second work areafor the mower 100. In this example, the user can then drive the moweralong the concrete path 816 towards the front lawn 810 andsimultaneously, set the mower to travel mode whilst the mower is on theconcrete path 814. This travel mode would set that this path travelledby the mower is for the transportation of the mower towards a secondwork area and thus the blades of the mower 100 do not need to be powered(as there is no grass to be cut in during its movement on the concretepath). This is advantageous in that power can be saved if the concretepath 814 is of some distance, thus extending the operation of the mower100 as well as enhancing the safety of the mower 100 as the operation ofthe blades is minimized. During its drive through the concrete path, themower 100 is continuously activating its navigation system so as tosurvey the areas around the path to its second operating area (frontlawn 810).

Once the mower reaches the front lawn 810, the user can drive the moweralong the perimeter 818 of the front lawn so as to set the working areaof the front lawn 810. In a similar manner to that of the back lawn 812,the mower is once again surveying its surrounding areas with itsnavigation system.

After the work area is defined, the user may then drive the mower 100back to its docking station 816 which will in turn record a return pathfor the mower 100. However, as the navigation system of the mower cansurvey its surrounding areas, it may be able to find its path back tothe docking station 816 since its travel paths have previously beenrecorded when the user had driven the mower from the docking station 816to the front lawn 810.

With reference to FIG. 9, there is provided a block diagram illustratingthe process flow of the initialization process of the autonomous mower100. As illustrated in this Figure, the user may start to issue commandsto the mower to drive the mower. These commands are received (902) andprocessed (904) by the controller 202 so as to drive the mower 100 alonga surface.

Meanwhile, the navigation system is operated (906) so as continuouslysurvey and records any navigation information for the mower during itsinitialization process. The navigation system may then active each ofits navigation modules 910 (IMU, Odometry, SONAR, LIDAR and othersensors) to record such navigation information (908) which can be usedfor navigation purposes when the mower is put into autonomous operation.

With reference to FIG. 10, there is provided an illustration of anautonomous lawn mower 100 comprising: a mower body 102 having at leastone motor arranged to drive a cutting blade 212 b and to propel themower body 102 on an operating surface via a wheel arrangement, whereinthe mower body 102 includes a navigation system 204 arranged to assist acontroller 202 to control the operation of the mower body 102 within apredefined operating area; and a battery module 1000 arranged to providepower supply to the motor; wherein the battery module 1000 is placed ata lower position within the rear mower body 102.

In this embodiment as shown in FIG. 10, the autonomous lawn mower 100 isprovided a battery module 1000 within the rear mower body 102 at a lowerposition adjacent to and between the two rear wheels. The battery module1000 is received by a battery holder 1010 resting on the mower body 102and positioned at a titled angle with respect to the operating surface.For instance, one end of the battery module 1000 is projected downwardsand towards the rear end of the mower body 102, such that the user mayaccess the battery module 1000 through an opening of the lower rearmower body 102.

Preferably, the mower body is further provided a battery cover 1020 toenclose the opening of the mower body 102, thereby preventing any dustor mowed grass from reaching the interior of the mower body 102.Optionally, the battery cover 1020 may be secured to the mower body 102firmly by coupling means 1030 such as screws.

With reference to FIGS. 11 to 13, there is provided an illustration ofan autonomous lawn mower 100 comprising: a mower body 102 having atleast one motor arranged to drive a cutting blade 212 b and to propelthe mower body 102 on an operating surface via a wheel arrangement,wherein the mower body 102 includes a navigation system 204 arranged toassist a controller 202 to control the operation of the mower body 102within a predefined operating area; wherein the mower body 102 furtherincludes a height adjustment system 1100 arranged to assist thecontroller 202 to control the operation of the cutting blade 212 bwithin a predefined operating height.

In this embodiment as shown in FIGS. 11 to 13, the autonomous lawn mower100 includes a height adjustment system 1100 comprising a heightadjustment motor 1110, a worm shaft 1120 driven by the height adjustmentmotor 1110, a micro switch 1130, and a hall sensor 1140.

Advantageously, the motor 1110 may manipulate the rotating direction ofthe worm shaft 1120 in clockwise or anticlockwise directions, such thatthe height of the cutting blade 212 b with respect to the operatingsurface may be manipulated by the motor 1110 indirectly.

The motor 1110 may be secured to the mower body 102 and remainsstationary throughout the height adjusting operations. For instance, thecutting blade 212 b may be moved towards the operating surface when theworm shaft 1120 rotates in a clockwise direction, and on the other hand,moved further away from the operating surface when the worm shaft 1120rotates in an anti-clockwise direction.

Optionally, the mechanical transmission between the motor 1110 and thecutting blade 212 b through the worm shaft 1120 may be enhanced by theuse of a ring shaped structure 1150. In this embodiment, the ring shapedstructure 1150 preferably comprises a plurality of bushings 1152, e.g.made of Polyoxymethylene (POM), a plurality of linear bearings 1156, oralternatively a combination thereof for supporting the height adjustmentsystem 1100. Advantageously, the linear bearing 1156 may counter thetorsional force induced by the distance between the worm shaft 1120 andthe opposite support.

In one embodiment, the plurality of bushings 1152 may be disposed aboutthe blade motor 212. A plurality of through holes 1154 may be disposedpreferably equidistantly for receiving these bushings 1152, and at leastone linear bearing 1156 may be disposed about the lower end of thebushing 1152 opposed to the worm shaft 1120. During the height adjustingoperation, the ring shaped structure 1150 may reinforce the worm shaft1120, such that the rotational force of the motor 1110 is converted intolateral forces steadily without out any vibrations or at least withminimal vibrations.

Although the worm shaft 1120 is located eccentrically to the centralaxis of the height adjustment system 1100 and it may inevitably exert aside loading against the height adjustment system 1100, the linearbearing 1156 may advantageously reduce the friction between the shaft1120 and the ring shaped structure 1150 due to the bending moment.Accordingly, the rotational force of the motor 1110 is converted intolateral forces steadily without transmitting the bending moment to theheight adjustment system 1100.

In this embodiment as shown in FIG. 13, the micro switch 1130 isdisposed on the blade motor 212, with a thin and elongated portion 1132further extended away from the blade motor 212 and towards the innermower body 102. Preferably, the hall sensor 1140 is disposed on top ofthe motor 1110 for detecting the presence of the elongated portion 1132of the micro switch 1130, thereby determining if the cutting blade 212 bhas reached the maximum height with respect to the operating surface.Advantageously, the hall sensor 1140 may further derive the number ofrotations required by the motor 1110 to reach the predefined desirableoperating height, and in turn assist the controller 202 to control theoperation of the cutting blade 212 b.

Optionally, the combination of micro switch 1130 and hall sensor 1140may be substituted by sensors e.g. photoelectric sensors. For instance,the photoelectric sensor may provide a signal to the height adjustmentsystem 1100, indicating the height position of the cutting blade 212 b,upon detecting the presence of the elongated portion 1132, oralternatively in the absence of the elongated portion 1132. It wouldalso be appreciated by person skilled in the art that the sensingfunction may be achieved by other alternative sensing means.

With reference to FIG. 14, there is provided an illustration of anautonomous lawn mower 100 comprising: a mower body 102 having at leastone motor arranged to drive a cutting blade 212 b and to propel themower body 102 on an operating surface via a wheel arrangement, whereinthe mower body 102 includes a navigation system 204 arranged to assist acontroller 202 to control the operation of the mower body 102 within apredefined operating area; wherein the cutting blade 212 b is pivotallyconnected to and driven by a motor-driven disc 211.

In this embodiment as shown in FIG. 14, the autonomous lawn mower 100further includes a motor-driven disc 211, a plurality of cutting blades212 b e.g. razor blades attached to the outer circumference of themotor-driven disc 211 through a specific arrangement. In thisarrangement, the cutting blades 212 b are mounted to the motor-drivendisc 211 with a spacer 213 therebetween, such that the cutting blades212 b are not fixed and allowed for certain degree of free rotations.

For instance, the cutting blade 212 b may swing in a first directioncorresponds to the rotating direction of the motor/motor-driven disc 211by the motor-driven disc 211 i.e. swing outward for cutting operation,and alternatively, swing in a second direction opposite to the firstdirection or the rotating direction of the motor/motor-driven disc 211i.e. swing inward and away from the obstacles if the cutting blade 212 bcontacts any obstacles.

This is especially advantageous over conventional lawn mowers where theobject to be trimmed is surrounded by obstacles with high stiffness. Insuch situation, by allowing the cutting blade 212 b to swing back andforth, this arrangement acts as a resilient means for damping the impactforce exerted on the cutting blade 212 b by the obstacle, such that thecutting blade 212 b may swing inward without absorbing the force by theengaging mechanism i.e. the spacer 213 between the cutting blades 212 band the motor-driven disc 211.

Subsequently, the cutting blade 212 b may swing towards the object to betrimmed through the centrifugal force of the motor-driven disc 211. Thisensures that the desired orientation of the cutting blades 212 b ismaintained throughout the trimming operation, such that the sharp edgeon the cutting blades 212 b is always facing/normal to the object to betrimmed.

While conventional lawn mowers require frequent adjustment of thecutting blades orientation, and at worst, the replacement of the screwsfixing the cutting blades to the motor-driven disc after a shortoperating cycle, the present embodiment provides an enhanced trimmingexperience, for example, prolonged lifespan, less maintenance orrepairing over conventional lawn mowers.

With reference to FIG. 15, there is provided an illustration of anautonomous lawn mower 100 comprising: a mower body 102 having at leastone motor arranged to drive a cutting blade 212 b and to propel themower body 102 on an operating surface via a wheel arrangement, whereinthe mower body 102 includes a navigation system 204 arranged to assist acontroller 202 to control the operation of the mower body 102 within apredefined operating area; wherein the mower body 102 further includes acutter module 1500 arranged to trim the edges of the predefinedoperating area.

In this embodiment as shown in FIG. 15, the autonomous lawn mower 100includes a cutter module 1500 comprising a perimeter cutter 1510 fortrimming the edges of a predefined operating area, and a lockingmechanism 1520 for engaging the cutter module 1500 with the mower body102. For instance, the locking mechanism 1520 may provide a male matingportion 1522 on the cutter module 1500 for engaging with a female matingportion 1524 provided on the mower body 102 positioned e.g. underneaththe mower body 102 and adjacent to the operating circumference of thecutting blade 212 b, such that the mower body 102 and the cutter module1500 are electrically communicated.

Advantageously, the locking mechanism 1520 may further provide a pushbutton 1526 to disengage the male mating portion 1522 from the femalemating portion 1524, thereby removing the cutter module 1500 from themower body 102 instantly. Optionally, there may be further provided acover 1530 for enclosing the female mating portion 1524 when the lawnmower 100 is operated without the cutter module 1500.

With reference to FIG. 16, there is provided an illustration of anautonomous lawn mower 100 comprising: a mower body 102 having at leastone motor arranged to drive a cutting blade 212 b and to propel themower body 102 on an operating surface via a wheel arrangement, whereinthe mower body 102 includes a navigation system 204 arranged to assist acontroller 202 to control the operation of the mower body 102 within apredefined operating area; wherein at least part of the cutting blade212 b is surrounded by a blade guard 1600.

In this embodiment as shown in FIG. 16, the autonomous lawn mower 100includes a blade guard 1600 for surrounding the cutting blade 212 b. Onthe front edge of the blade guard 1600 which is substantiallyperpendicular to the operating direction of the autonomous lawn mower100, there is provided a toothed comb 1610 between the two front wheelsfor combing the grass to be mowed before being trimmed by the cuttingblade 212 b. Advantageously, the toothed comb 1610 may minimise theundesirable interruption of the mowing operation by over-sized objects,thereby enhancing the efficiency of the cutting operation to a certaindegree. Optionally, a plurality of protection ribs 1620 may also beprovided on the side edges of the blade guard 1600 to prevent anyundesirable objects from reaching the cutting blade 212 b from the sidedirections.

With reference to FIGS. 17 to 20, there is provided an illustration ofan autonomous lawn mower 100 comprising: a mower body 102 having atleast one motor arranged to drive a cutting blade 212 b and to propelthe mower body 102 on an operating surface via a wheel arrangement,wherein the mower body 102 includes a navigation system 204 arranged toassist a controller 202 to control the operation of the mower body 102within a predefined operating area; a battery module 1000 arranged toprovide power supply to the motor; and a detachable docking module 900arranged to provide battery charging to the battery module 1000.

In this embodiment as shown in FIGS. 17 to 18, the autonomous lawn mower100 includes a battery module 1000 for providing power supply to themotor, a detachable docking module 900 in electrical communication witha power plug for charging the battery module 1000, and a navigationsystem 204 for locating the mower 100 with reference to the position ofthe docking module 900. Advantageously, upon completing the moweroperation or if the power level of the battery module 1000 is runninglow during mid of the operation, the navigation system 204 may direct orguide the mower 100 towards the docking module 900 through a “docking”process, such that the mower 100 may be switched off and/or the batterymodule 1000 may be recharged once the mower 100 is received by thedocking module 900.

Preferably, the navigation system 204 may include an imaging module 205,e.g. a web camera 205 for obtaining the information associated with theposition of the docking module 900. On the other hand, the dockingmodule 900 may provide the imaging module 205 an indication 910representing the position of the docking module 900.

Preferably, the indication 910 may be represented in a graphicalrepresentation at a visible area on the docking module 900 (as shown inFIG. 19), thereby allowing the imaging module 205 to capture theindication 910, and in turn calculate the present position of the mower100 with respect to the docking module 900 through an image processingbased on the rotation and distortion of the captured indication 910.Optionally, each indication 910 may provide a unique ID, such that onemower 100 may only map with one designated docking module 900.

Alternatively, the navigation system 204 may include an opticalsurveying module 222 for obtaining the information associated with theposition of the docking module 900. For instance, the optical surveyingmodule 222 may be the aforesaid single LIDAR unit 222L. Preferably, theLIDAR unit 222L may scan and survey the proximate area around the mower100 to devise the surveyed representation of the predefined operationarea. The optical surveying module 222 may then map the target LIDARobject with the sensed LIDAR object with the closest dimension to thedocking module 900, thereby locating the position of the docking module900, or determining the present position of the mower 100 with referenceto the position of the docking module 900.

In yet another embodiment as shown in FIG. 20, the navigation system 204may include an induction wire system 240 for obtaining the informationassociated with the position of the detachable docking module 900. Forinstance, the induction wire system 240 may include a plurality ofsensors 242, 244 and 246 positioned at any desirable positions withinthe mower 100. On the other hand, the docking module 900 may provide acore 248 (not shown) for communicating with the sensors 242, 244 and 246in an electromagnetic communication. Preferably, the induction wiresystem 240 may calculate the present position of the mower 100 withrespect to the docking module 900 based on the electromagneticcommunication between the sensors 242, 244, 246 and the core 248 in arepetitive manner, thereby providing a docking assistance to the mower100 during the docking process.

Although not required, the embodiments described with reference to theFigures can be implemented as an application programming interface (API)or as a series of libraries for use by a developer or can be includedwithin another software application, such as a terminal or personalcomputer operating system or a portable computing device operatingsystem. Generally, as program modules include routines, programs,objects, components and data files assisting in the performance ofparticular functions, the skilled person will understand that thefunctionality of the software application may be distributed across anumber of routines, objects or components to achieve the samefunctionality desired herein.

It will also be appreciated that where the methods and systems of thepresent invention are either wholly implemented by computing system orpartly implemented by computing systems then any appropriate computingsystem architecture may be utilised. This will include stand alonecomputers, network computers and dedicated hardware devices. Where theterms “computing system” and “computing device” are used, these termsare intended to cover any appropriate arrangement of computer hardwarecapable of implementing the function described.

It will be appreciated by persons skilled in the art that numerousvariations and/or modifications may be made to the invention as shown inthe specific embodiments without departing from the spirit or scope ofthe invention as broadly described. The present embodiments are,therefore, to be considered in all respects as illustrative and notrestrictive.

Any reference to prior art contained herein is not to be taken as anadmission that the information is common general knowledge, unlessotherwise indicated.

1. An autonomous lawn mower comprising: a mower body having at least onemotor arranged to drive a cutting blade and to propel the mower body onan operating surface via a wheel arrangement, wherein the mower bodyincludes a navigation system arranged to assist a controller to controloperation of the mower body within a predefined operating area; and abattery module arranged to provide power supply to the motor; whereinthe battery module is placed at a lower position within a rear end ofthe mower body.
 2. The autonomous lawn mower of claim 1, wherein thebattery module is arranged at a tilted angle with respect to theoperating surface to facilitate access to the battery module.
 3. Theautonomous lawn mower of claim 2, wherein the mower body is furtherprovided a battery cover arranged to cover the access to the batterymodule.
 4. An autonomous lawn mower comprising: a mower body having atleast one motor arranged to drive a cutting blade and to propel themower body on an operating surface via a wheel arrangement, wherein themower body includes a navigation system arranged to assist a controllerto control operation of the mower body within a predefined operatingarea; wherein the mower body further includes a height adjustment systemarranged to assist the controller to control the operation of thecutting blade within a predefined operating height.
 5. The autonomouslawn mower of claim 4, wherein the height adjustment system includes oneor more sensors arranged to determine the height of the cutting blade.6. The autonomous lawn mower of claim 5, wherein the height adjustmentsystem is arranged to communicate with the one or more sensors todetermine a number of rotations required by the cutting blade to reachthe predefined operating height.
 7. An autonomous lawn mower comprising:a mower body having at least one motor arranged to drive a cutting bladeand to propel the mower body on an operating surface via a wheelarrangement, wherein the mower body includes a navigation systemarranged to assist a controller to control operation of the mower bodywithin a predefined operating area; wherein the cutting blade ispivotally connected to and driven by a motor-driven disc.
 8. Theautonomous lawn mower of claim 7, wherein the cutting blade is arrangedto swing in a first direction by the motor-driven disc and swing in asecond direction in response to the cutting blade contacting anobstacle.
 9. The autonomous lawn mower of claim 8, wherein the firstdirection corresponds to a rotating direction of the motor and thesecond direction is opposite to the first direction.